When a person is looking forward, the center of gravity of the person's head is above and approximately in vertical alignment with the person's spine. With the person's head in this forward looking position, the weight of the person's head is supported by the spine, much like a column supports the weight of a building roof. However, when the person is looking upwards, the person's head will tilt backwardly and move the person's head out of vertical alignment with the spine. When the head is tilted backwards, the center of gravity of the head moves rearwardly of the spine and the person's neck muscles must support the weight of the head. Supporting the head in this backward tilted position requires more energy and effort from the neck muscles than is normally required when holding the head in an upright, forward looking position. If the person is looking upward for extended periods, the additional energy and effort expended by the neck muscles will soon result in discomfort and fatigue as the neck muscles begin to tire.
Headrests have been developed and used by people who must look upwardly for extended periods. These prior art headrests have been used by plasters, travelers, and mechanics who must hold their heads in a backward tilted position for extended periods. The primary purpose of these prior art headrests has been to provide the necessary head support to reduce neck fatigue. These prior art headrests usually rest on and derive support from the person's shoulders, or, are attached to the person's belt. Prior art headrests attaching to the person's belt may not be comfortable if the belt is pulled upwards and purchases itself under the person's ribs restricting the diaphragm, or if the person's pants are elevated until the pants crotch finds purchase on the body.
Recreational sporting activities can require the participant to look upward for extend periods. For example, when rock or mountain climbing or mountaineering, a belayer is responsible for the climbers safety by feeding the proper amount of rope to the climber through a friction creating device attached to the belayers harness. Maintaining the proper amount of rope tension requires that the belayer keep the climber in eye contact whenever possible. Since the climber moves upward from the belayers position, the belayer is required to keep the head tilted backward at a sever angle for extended periods of time.
Some individuals have difficulty or require assistance in holding their heads in a vertical position. For example, individuals with physical disabilities, people recovering from neck or head injury, or people suffering from chronic muscle spasms may require neck and/or head support.
Several key features have been lacking in these prior art headrests. One lacking feature is the construction of a headrest which provides adequate support to the back of the neck and the head, and which can be securely and comfortably mounted to the person. Another feature lacking in some prior art headrests is a simple construction of only one or two pieces, thereby minimizing the cost of production and simplifying the assembly process. Another lacking feature is a headrest which provides support at a selectable angle, or over a continuous angle range of backwardly tilted head positions. Also, many of the prior art head supports do not provide a back mounted support plate which is contoured or shaped to the person's shoulder blades, nor do the prior art back mounted support plates provide a space for the person's spinal cord, which would minimize discomfort to the person, reduce movement of the head support, and increase stability of the back mounted support plate when attached to the person's back.